(1) Field of the Invention
This application relates to bis(aminoethanethiol) compounds and salts thereof useful as intermediates in the preparation of image dye-providing materials for use in photographic applications.
(2) Description of the Related Art
U.S. Pat. No. 3,719,489 describes and claims photographic processes employing initially photographically inert compounds which are capable of undergoing cleavage in the presence of silver ions made available imagewise during processing of a silver halide emulsion to liberate a reagent, such as, a photographically active reagent or a dye in an imagewise distribution corresponding to that of said silver ions. In one embodiment disclosed therein, color images are produced by using as the photographically inert compounds, dyes which are substantially nondiffusible in the photographic processing composition but capable of undergoing cleavage in the presence of the imagewise distribution of silver ions and/or soluble silver complex made available in the undeveloped and partially developed areas of a silver halide emulsion as a function of development to liberate a more diffusible dye in an imagewise distribution corresponding to the imagewise distribution of said ions and/or said complex. The formation of a color image is the result of the differential in diffusibility between the parent compound and the liberated dye whereby the imagewise distribution of the more diffusible dye released in the undeveloped and partially developed areas is free to transfer. Color-providing compounds useful in the above processes form the subject matter of U.S. Pat. No. 4,098,783, a continuation in part of said U.S. Pat. No. 3,719,489.
Among the color-providing materials disclosed in the aforementioned U.S. Pat. No. 4,098,783 are the thiazolidine dyes comprising a substituted or unsubstituted thiazolidine group and a complete dye, e.g., ##STR1## As described therein, these thiazolidine dyes can be prepared by condensing a dye-substituted aldehyde, i.e., DYE-CHO, with an aminoethanethiol, e.g., ##STR2##
Copending application Ser. No. 923,843, filed Jul. 31, 1992 of M. Arnost, E. Chinoporos, D. McGowan and D. Waller, filed on even date herewith, discloses certain color-providing compounds, useful in the processes described in the aforementioned U.S. Pat. No. 3,719,489 and in thermally developed silver halide photographic processes such as disclosed in Japanese Kokai 59-180548, having a Laid-Open date of Oct. 13, 1984. A preferred embodiment of the color-providing compounds disclosed in the aforementioned copending application Ser. No. 923,843, filed Jul. 31, 1992 is represented by the formula ##STR3## wherein D represents a complete dye, i.e., a dye radical of an organic dye; L represents a divalent organic linking group containing at least one carbon atom; m is 0 or 1; X represents a chemical linkage joining the two cyclic 1,3-sulfur-nitrogen groups; R.sub.1 represents hydrogen, a monovalent organic radical or together with L represents the atoms necessary to complete a spiro union with one of the cyclic 1,3 sulfur-nitrogen groups when m is 1 or together with D represents the atoms necessary to complete a spiro union with one of the cyclic 1,3-sulfur-nitrogen groups when m is 0; and R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are each independently hydrogen, a monovalent organic radical or taken together, R.sub.3 and R.sub.4 or R.sub.5 and R.sub.6 represent a substituted or unsubstituted carbocyclic or heterocyclic ring. Upon silver ion assisted cleavage, these color-providing compounds release a diffusible dye.
The present application is directed to bis(aminoethanethiol) compounds which are useful as intermediates in the preparation of the compounds of Formula I.